Your aptitude in mechanics, agriculture, weather, hunting, medicine, guerrilla warfare and good old-fashioned American know-how. Some things you can do: Drill a well (easy), dig a tunnel (average), repair an internal combustion engine (difficult), disguise your home from casual reconnaissance (average), stand a solid 12 hour watch (easy), perform basic first aid (v. difficult). Hiding, sneaking scouting and sniping along the countryside.